The air we breathe out can help us improve the quality of the air we breathe in.
Measurements of indoor carbon dioxide (CO2) concentrations are used to evaluate indoor air quality, which is strongly linked to the levels of contaminants, such as gases and particles, circulating about with CO2. This information also can be used to control ventilation, which helps clean the air, and reduce the need for heating and cooling, which saves energy. However, according to National Institute of Standards and Technology (NIST) mechanical engineer Andrew Persily and George Mason University nutrition professor and human metabolism scientist Lilian de Jonge, the formula that’s been used since the early 1980s to estimate an integral part of those calculations—the amount of CO2 generated by building occupants—relies on old data and a method lacking scientific documentation. This means current estimates of CO2 generation rates may be off by as much as 25 percent.
The air we breathe out can help us improve the quality of the air we breathe in.
Measurements of indoor carbon dioxide (CO2) concentrations are used to evaluate indoor air quality, which is strongly linked to the levels of contaminants, such as gases and particles, circulating about with CO2. This information also can be used to control ventilation, which helps clean the air, and reduce the need for heating and cooling, which saves energy. However, according to National Institute of Standards and Technology (NIST) mechanical engineer Andrew Persily and George Mason University nutrition professor and human metabolism scientist Lilian de Jonge, the formula that’s been used since the early 1980s to estimate an integral part of those calculations—the amount of CO2 generated by building occupants—relies on old data and a method lacking scientific documentation. This means current estimates of CO2 generation rates may be off by as much as 25 percent.
To help address the problem, Persily and de Jonge have developed a new computation method that uses well-established concepts from the study of human metabolism and exercise physiology relating CO2 generation rates to body size and composition, diet and level of physical activity. This results in more accurate estimates of the CO2 generated by individuals, the researchers said, which subsequently yields an improved estimate of the concentration produced by a building’s entire occupant population.
Continue reading at National Institute of Standards and Technology
Image: A new method for calculating concentrations of carbon dioxide, seen here as soda bubbles, will significantly improve the measurements used to evaluate indoor air quality. Credit: M.E. Newman / NIST
